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Influence of electron–phonon interaction on the properties of transport through double quantum dot with ferromagnetic leads

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Chinese Physics B 2014年第10期23卷 447-457页

作者：罗侃王发强梁瑞生任珍珍 Laboratory of Nanophotonic Functional Materials and Devices (SIPSE) and Laboratory of Quantum Engineering and Quantum MaterialsSouth China Normal University

electronic transport through a vibrating double quantum dot （DQD） in contact with noncollinear ferromagnetic （FM） leads is investigated. The state transition between the two dots of the DQD is excited by an AC microwave driving field. The corresponding currents and differential conductance are calculated in the Coulomb blockade regime by means of the Born-Markov master equation. It is shown that the interplay between electrons and phonons gives rise to phonon-assisted tunneling resonances and Franck-Condon blockade under certain conditions. In noncollinear magnetic configurations, spin-blockade effects are also observed, and the angle of polarization has some influence on the transport characteristics.

关键词： electron-phonon spin-polarized transport negative differential conductance

Properties of nonadiabatic quantum fluctuations of the strongly coupled electron-phonon systems

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Science China(Physics,Mechanics & Astronomy) 2008年第3期51卷 258-268页

作者： PANG XiaoFeng Institute of Life Science and Technology,University of electronic Science and Technology of China,Chengdu 610054,China International Centre for Materials Physics,Chinese Academy of Sciences,Shenyang 110015,China Institute of Life Science and Technology University of Electronic Science and Technology of China Chengdu China International Centre for Materials Physics Chinese Academy of Sciences Shenyang China

A new variational-ansatz of states of electrons and phonons was proposed on the basis of the Holstein model in strongly coupled electron-phonon systems for studying the influence of nonadiabatic phonon fluctuation,arising from the motion and density fluctuation of electrons,on the properties of ground state,uncertainty relation,stability of polarons,charge density wave (CDW) and phonon staggered ordering. The new ansatz represents the correlation among the displacement and squeezing states of phonons and polaron’s state of electrons as well as the squeezing-antisqueezing effect. The correlation and squeezing-antisqueezing ef-fect result in the decrease of ground state energy,enhancement of stability of the systems,increase of binding energy of the polarons,weakening of the growing speed of polaron narrowing of the electron band,increase of the charge density wave order and suppression of the increased tendency of anomalous quantum fluctuation of the phonons in such a case,when compared with the uncorrelated case in the systems. The results obtained show that the ground state determined by the new state ansatz is most stable,thus the new ansatz describing the properties of the coupled electron phonon systems is very relevant and available,especially in strongly coupled and largely squeezed cases.

关键词： squeezing-antisqueezing effect state-ansatz polaron coupled electron-phonon systems quantum fluctuation

The effect of the electron-phonon coupling on single-layer Buckyonions

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Science China Mathematics 1996年第1期39卷 78-84页

作者：王志坚罗民兴李文铸曹志良韩汝珊 Department of Physics Zhejiang University Hangzhou 310027 China Department of Physics Peking University Beijing 100871 China

The electronic and the geometric structures of the metallic and the semiconducting carbon onions are studied. Taking into account the electron-phonon coupling, both classes of onions are found to suffer Peierls instability. Also, the C-C bonds are dimerized, the binding energies are increased, and the energy gaps are enlarged. The symmetries of the geometric and the electronic structures of metallic onions are reduced, while those of semiconducting onions are not. The distortions of the structures decrease as the number of carbon atoms increases. The dimerization patterns of these onions are also presented.

关键词： Buckyonion electron-phonon couple.

Dynamic Deformation electron-phonon Interaction in Disordered Bulk Semiconductor

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World Journal of Condensed Matter Physics 2012年第1期2卷 42-46页

作者： Pushpendra Tripathi Syed Sikandar Zulqarnyn Ashraf Syed Tahir Hasan Ami Chand Sharma Aligarh Muslim University Aligarh India Shibli National Post Graduate College Azamgarh India The Maharaja Sayajirao University of Baroda Vadodara India

We present our theoretical investigations on the effects of disorder on the electron-phonon interaction in semiconducting GaAs system. Both the temperature (T) and disorder (electron mean free path l) dependences of the electron-phonon scattering rate have been determined. On consideration of the dynamic screening, we find a significant change in the temperature exponent as well as the pre factor from the earlier reported temperature power law dependence result ?T6 obtained under static screening. Also the dynamic screening makes a noticeable change in the character of the dependence of scattering rate on the mean free path from the static screening result.

关键词： electron-phonon Scattering Rate Dynamic Screening Deformation Potential

Theoretical Calculations of Thermal Broadenings and Transition Probabilities of R, R＇ and B Line-Groups for Ruby

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Communications in Theoretical Physics 2001年第12期36卷 723-728页

作者： MA Dong-Ping LIU Yan-Yun CHEN Ju-Rong Department of Applied Physics Sichuan University Chengdu 610065 China International Centre for Materials Physics The Chinese Academy of Sciences Shenyang 110015 China Department of Applied Physics Sichuan University Chengdu 610065 China Department of Applied Physics Sichuan University Chengdu 610065 China

On the basis of the unified calculation of the thermal shifts of R1 line, R2 line and ground-state-splitting transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings of R,The theoretically predicted transition probabilities are in good agreement with the experimental *** numbers: ***, ***, ***, 63.20.

关键词： crystal fields, electron-phonon interaction, thermal broadening, transition probability, direct and Raman processes

Energy Spectra, g Factors and Their Pressure-Induced and/or Thermal Shifts of SrTiO3:Cr3+ and SrTiO3:Mn4+ Ⅲ: R-Line Thermal Shifts of SrTiO3:Mn4+

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Communications in Theoretical Physics 2001年第11期36卷 463-468页

作者： MA Dong-Ping ZHANG Ji-Ping Department of Applied Physics Sichuan University Chengdu 610065 China International Centre for Materials Physics The Chinese Academy of Sciences Shenyang 110015 China Department of Applied Physics Sichuan University Chengdu 610065 China

By taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of basic wavefunctions within d3 electronic configuration,the values of the parameters in the expressions of thermal shift (TS) from EPI for the ground level, R level and R line of SrTiO3:Mn4+ have been evaluated; the R-line TS and various contributions to it have been calculated in the low-temperature region. It is found that all the three terms of R-line TS from EPI relevant to the lattice vibration are red shifts. The Raman term is the largest, the neighbor-level term is the second, and the optical-branch term is very small over the range of T ≤ 80 K. The contribution to R-line TS from thermal expansion has been approximately neglected in this work. The very strong EPI relevant to its lattice vibration for SrTiO3:Mn4+ causes its R-line TS to be an unusually large red-shift. Only by taking into account the strong softening of the low-frequency acoustic modes of the lattice vibration at low temperatures, can we successfully explain the variation of R-line TS of SrTiO3:Mn4+ with temperature.

关键词： crystal fields, optical properties, electron-phonon interaction, thermal shift, softening of acoustic modes

Theory of Triple Magnetopolarons in Quantum-Dimensional Nanostructures

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American Journal of Analytical Chemistry 2013年第9期4卷 457-463页

作者： Barat Eshpulatov Eshkuvat Arzikulov Samarkand branch of Tashkent Information Technology University Samarkand Uzbekistan Samarkand State Universiy Samarkand Uzbekistan

A theory of triple magnetopolarons in an isolated quantum well in a strong magnetic field was developed. We study the behavior of the magnetooptical absorption peaks corresponding to the transitions of an electron at the Landau level with quantum numbers n ≥ 2. For n = 2 at the point of equality of cyclotron frequency and the frequency of optical phonon (LO), there is a cross of three terms of the electron-phonon system (the electron at the Landau level n = 2, the electron at n = 1, and the optical phonon and electron at n = 0 and two phonons), considered as a function of the cyclotron frequency. Interaction with phonons takes off the degeneracy of the terms and leads to three disjoint branches of the electron-phonon spectrum. The theory predicts that in the resonant magnetic field, the peak of magnetooptical absorption splits into three peaks, the intensity and position of which are dependent in a complex way on the magnitude of the magnetic field and the constant of the electron-phonon coupling.

关键词： Triple Magnetopolarons Quantum-Dimensional Nanostucrures electron phonons electron-phonon Spectrum Magnetooptical Absorption Resonant Magnetic Field

Impact of phonon-assisted tunneling on electronic conductivity in graphene nanoribbons and oxides ones

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Natural Science 2010年第9期2卷 979-983页

作者： Povilas Pipinys Antanas Kiveris 不详

phonon-assisted tunneling (PhAT) model is applied for explication of temperature-dependent conductivity and I-V characteristics measured by various investigators for graphene nanoribbons and oxides ones. Proposed model describes well not only current dependence on temperature but also the temperature-dependent I-V data using the same set of parameters characterizing material under investigation. The values of active phonons energy and field strength for tunneling are estimated from the fit of current dependence on temperature and I-V/T data with the phonon-assisted tunneling theory.

关键词： electronic Transport in Graphene phonon-Assisted Tunneling electron-phonon